SimScale CAE Forum

Similar Freq, diff mode shapes

Modes

I have got equal frequencies in consecutive modes(as seen in the pic) , although the mode shapes are equal, but perpendicular to each other.

I would like to know what we can infer from this result?

Hey @sgeorge!

Do you have a project link for us? And try to use a 2nd order mesh and tweak the mesh fineness a bit as this has at least to my knowledge tremendous effects on the results.

Best,

Jousef

1 Like

More interestingly…which tool did you use?
I guess that’s not done with SimScale?

In general multiple mode shapes at the same frequency are perfectly fine and just a result of the symmetries in the model.

The fact that the modes of the same frequency are orthogonal tells you that there are basically infinitely many Eigenmodes spanning over a whole plane of possible modes with the exact same frequency but just rotated coordinate system.

Best,
Richard

Thanks. This was done with Nx CAE.

Its clear now that the results show similar modal frequencies and different mode shapes due to the symmetrical nature of the 1D beam element.